gwc - gas water condensing installation manual (38.64 mb)

Model

GWC

Installation

Startup

Maintenance

Parts

Boiler Manual

This manual must only be used by a qualified heating installer/service technician. BEFORE installing, read all instructions in this manual and all other information shipped with the boiler. Perform steps in the order given. Failure to comply could result in severe personal injury, death or substantial property damage.

Series 2

Gas-Fired Water Boilers

Part number 550-142-786/0712

How it works . . .

LEGEND

a Supply to system, 1 NPT

b Return from system, 1 NPT

c Combustion air inlet fitting 3 PVC connection

d Flue outlet 3 PVC connection

e Gas valve negative pressure regulated gas control

f Pressure/temperature gauge

g Flueway inspection port cover

h Sensor hose trap

i Manual air vent

j Relief valve

k Thermal fuse a one-time fuse device that shuts boiler off if flue temperature exceeds its setpoint

m Condensate trap line shipped loose with boiler, field installed

n Condensate drain connection PVC female

This boiler uses a negative-pressure-regulated gas valve, set for an outlet pressure approximately 0.20 water column.

DO NOT set the outlet pressure higher than factory setting.

Part number 550-142-786/07122

GWC SerieS 2 gaS-fired water boiler Boiler Manual

1 Integrated boiler controlThe integrated boiler control (IBC) responds to signals from the room thermostat, air pressure switch, inlet water sensor, boiler water temperature sensor and boiler limit circuit to operate the circulators, gas valve, igniter and blower. When a room thermostat calls for heat, the IBC starts the system circulator and blower.The IBC runs the blower to purge the boiler flue passages, then turns on the igniter and lets it warm up.After igniter warm-up, the IBC opens the gas valve, turns the igniter off, and checks for flame. The flame must come on within 4 seconds or the IBC will shut down and try the full cycle again.When the room thermostat is satisfied, the IBC turns off the boiler components and waits for the next heat call.The IBC indicator lights show normal sequence when the lights are on steady. When a problem occurs, the IBC flashes combinations of lights which indicate the most likely reason for the problem.While attempting to satisfy the heat demand, the control module monitors the boiler temperature changes via the temperature sensors and determines whether or not the available hot water will satisfy the demand, only running the circulator. If additional heat is needed, the sequence continues. When DHW (if used) calls for heat, sequence above is bypassed.

2 TransformerThe control transformer reduces line voltage to 24 volts for the gas valve and limit circuit.

3 BlowerThe blower pulls in air and mixes it with gas from the gas valve. The blower forces this mixture into the burner for combustion inside the boiler chamber.

4 RecuperatorThe recuperator is a stainless steel heat exchanger that increases boiler efficiency by ex-tracting additional heat from the flue gases. Return water passes through the recuperator before entering the boiler.

5 Water temperature sensorThe water temperature sensor provides a signal to the control module to turn off the gas valve if the temperature in the boiler goes above its setting. (The circulator will continue to run as long as there is a call for heat.)

6 System circulatorThe system circulator circulates water through the external (system) piping. The flow rate of the circulator is controlled by the IBC, depending on the temperature of the water entering the boiler sections. Pump must remain on boiler do not remove.

7 Bypass circulatorThe IBC operates the bypass circulator to mix hot water from the boiler outlet with colder return water from the system as needed to prevent condensation of flue gases in the cast iron heat exchanger.

When the water returning to the boiler is below 140F, the IBC regulates the bypass circulator and system circulator flow rates to raise the return water temperature up to 140F before it enters the cast iron sections. By balancing these flow rates, the IBC can protect against condensation even if return water is as low as 60F.

Pump must remain on boiler do not remove.

8 Air pressure switchThe air pressure switch signals the IBC, telling the control whether air is moving through the blower.

9 Return water temperature sensorThe water temperature sensor monitors the temperature of the water entering the boiler sections. The sensor sends this information to the IBC. The IBC determines how much to adjust the circulator flow rates to provide at least 140F water to the cast iron heat exchanger.

GWC Series 2 Water Boiler

Part number 550-142-786/0712 3


How it works . . . . . . . . . . . . . .2

GWC Water Boiler . . . . . . . . . .3

Please read before proceeding . . .5

Prepare boiler location . . . . . . .6Installations must follow these codes: . . . 6High altitude installations. . . . . . . . . . 6Residential garage installation . . . . . . . 7Check orifice plate replace if necessary . 8Install condensate trap. . . . . . . . . . . . 9Install high altitude air pressure switch when required (only above 5,500 feet) . . . . . 10Rotate the boiler into position . . . . . . 10Perform hydrostatic pressure test . . . . . 11

Install water piping . . . . . . . . 12General piping information. . . . . . . . 12Install relief valve . . . . . . . . . . . . . 12Expansion tank. . . . . . . . . . . . . . . 13System water piping methods. . . . . . . 15Circulators . . . . . . . . . . . . . . . . . 15Simplified pipe/circulator selection . . . 15Baseboard system piping CIRCULATOR zoning (primary/secondary) 16Baseboard system piping ZONE VALVE zoning (direct connection) 16Radiator system piping . . . . . . . . . . 18Single-zone radiant heating or heat pump 19Adjust balancing valves . . . . . . . . . . 19Multi-zone radiant heating system . . . . 20Piping snow melt systems or combination snow melt/space heating systems . . . . . 21Water chiller systems . . . . . . . . . . . 22

Multiple boiler installations . . . . 23Placing multiple boilers . . . . . . . . . . 23Controlling multiple GWC boilers . . . . 23Piping multiple GWC boilers . . . . . . . 23

Multiple boiler water piping. . . . 24Secondary header piping installation. . . 24

Venting & air general . . . . . . 29When removing a boiler from an existing common vent system . . . . . . . . . . . 29Existing vent test procedure. . . . . . . . 29Provide combustion air: . . . . . . . . . . 30Vent and air termination options. . . . . 30DIRECT VENT installations . . . . . . . 30DIRECT EXHAUST installations. . . . . 30Combustion air contamination: . . . . . 30Manifolded combustion air option for DIRECT VENT multiple boiler installations 31Air manifold sizing . . . . . . . . . . . . 31

Commonwealth of Massachusetts installations . . . . . . . . . . . . 34

Vent termination requirements . . 35

DIRECT VENT Boiler room air openings . . . . . . . . . . . . . . 36

DIRECT VENT Sidewall with sepa-rate pipes. . . . . . . . . . . . . . 37

DIRECT VENT Sidewall with 3 concentric . . . . . . . . . . . . . 39

DIRECT VENT Vertical with sepa-rate pipes. . . . . . . . . . . . . . 41

DIRECT VENT Vertical with 3 concentric . . . . . . . . . . . . . 43

Concentric termination assembly (sidewall or vertical) . . . . . . . . 45

Vent and air piping and boiler con-nections . . . . . . . . . . . . . . 46

DIRECT EXHAUST & DIRECT VENT . 46Follow termination instructions . . . . . 46Installing vent and air piping . . . . . . . 46DIRECT EXHAUST ONLY . . . . . . . . 46

DIRECT EXHAUST Boiler room air openings . . . . . . . . . . . . . . 47

Combustion air provision. . . . . . . . . 47Sizing combustion air openings . . . . . 47Special considerations . . . . . . . . . . . 47GWC boiler WITHOUT other appliances in room. . . . . . . . . . . . . 48Air openings . . . . . . . . . . . . . . . . 48GWC boiler WITH other appliances in room. . . . . . . . . . . . . 48

DIRECT EXHAUST Sidewall . . 49

DIRECT EXHAUST Vertical . . . 51

Gas piping . . . . . . . . . . . . . 52Connecting gas supply piping. . . . . . . 52Natural Gas. . . . . . . . . . . . . . . . . 53Propane Gas . . . . . . . . . . . . . . . . 53

Wiring . . . . . . . . . . . . . . . 53Field wiring. . . . . . . . . . . . . . . . . 54

Start-up. . . . . . . . . . . . . . . 57Freeze protection (when used) . . . . . . 57Clean system to remove sediment . . . . 57Water chemistry . . . . . . . . . . . . . . 57Antifreeze. . . . . . . . . . . . . . . . . . 57Fill and test water system . . . . . . . . . 58Check for gas leaks. . . . . . . . . . . . . 59Verify gas/air orifice plate . . . . . . . . . 59Check thermostat circuit(s) . . . . . . . . 59Inspect/fill condensate system . . . . . . 59Final checks before starting boiler . . . . 60

Adjust boiler control settings . . . . . . . 60Ajust boiler control settings . . . . . . . . 60Boiler Economy settings. . . . . . . . . . 60 To start the boiler . . . . . . . . . . . . . 60If boiler does not start correctly . . . . . 60Check system and boiler after start-up . . 60Gas valve adjustment altitude over 5,500 feet ONLY . . . . . . . . . . . 61Final checklist . . . . . . . . . . . . . . . 62

Department of Energy Compliance . 63IBC (Sequence of operations). . . . . . . 64Operating Instrustions . . . . . . . . . . 65

Annual start-up and general mainte-nance schedule . . . . . . . . . . 66

Annual start-up . . . . . . . . . . 67

Address reported problems . . . . . . . . . 67Inspect boiler area . . . . . . . . . . . . . 67Inspect boiler interior . . . . . . . . . . . 67Inspect condensate drain system . . . . . 67Inspect all piping for leaks . . . . . . . . 67Inspect gas piping . . . . . . . . . . . . . 67Inspect the water system. . . . . . . . . . 67Check water system chemistry . . . . . . 67Inspect expansion tank . . . . . . . . . . 68Inspect air openings . . . . . . . . . . . . 68Inspect vent system and air piping . . . . 68Inspect boiler heating surfaces . . . . . . 68Inspect igniter . . . . . . . . . . . . . . . 68Inspect temperature mixing system . . . 69Inspect additional controls and cutoffs. . . . 69Inspect gauges . . . . . . . . . . . . . . . 69Inspect blower motor . . . . . . . . . . . 69Inspect oiled-bearing circulators . . . . . 69Inspect temperature sensor . . . . . . . . 69Inspect boiler relief valve . . . . . . . . . 70To complete Annual Start-up, perform startup and checks: . . . . . . . . . . . . 70Review with owner. . . . . . . . . . . . . 70

Service & maintenance . . . . . 71Cleaning boiler heating surfaces . . . . . 71Inspecting and cleaning the recuperator . 72

Troubleshooting . . . . . . . . . 74

VERIFY PROPER OPERATION AFTER SERVICING. . . . . . . . . . . . . . . . . 74Before troubleshooting . . . . . . . . . . 74Check the following . . . . . . . . . . . . 74Checking the air pressure switch . . . . . 74Igniter. . . . . . . . . . . . . . . . . . . . 75Gas Valve . . . . . . . . . . . . . . . . . . 75Blower Housing . . . . . . . . . . . . . . 75Thermal fuse . . . . . . . . . . . . . . . . 75Return temperature sensor . . . . . . . . 76Supply temperature sensor . . . . . . . . 76IBC (integrated boiler control) . . . . . . 77IBC indicator lights lockout modes . . 77IBC indicator lights non-lockout modes . . . . . . . . . . . . 77

Replacement parts . . . . . . . . 88

Dimensions and ratings. . . . . . 99

Notes . . . . . . . . . . . . . . . 104

Handling ceramic fiber and fiberglass materials . . . . . . . 106

Installation and service certificate . . . . . . . . . . . . 107

Contents

Part number 550-142-786/07124


Failure to adhere to the guidelines on this page can result in severe personal injury, death or substantial property damage.

When servicing boiler To avoid electric shock, disconnect electrical supply

before performing maintenance. To avoid severe burns, allow boiler to cool before

performing maintenance. This boiler contains ceramic fiber and fiberglass

materials. Refer to the WARNING and instructions on page 106.

Boiler operation Do not block flow of combustion or ventilation air

to boiler. Should overheating occur or gas supply fail to

shut off, DO NOT turn off or disconnect electrical supply to circulator. Instead, shut off the gas supply at a location external to the appliance.

Do not use this boiler if any part has been under water. Immediately call a qualified service techni-cian to inspect the boiler and to replace any part of the control system and any gas control that has been under water.

Combustion air DO NOT install combustion air intake where there

is a risk of combustion air contamination.

Carbon monoxide detector For Direct Exhaust units, a carbon monoxide detector

is required in the boiler room. The carbon monoxide detector must be wired on the same electrical circuit as the boiler.

For Direct Vent units, a carbon monoxide detector that is wired on the same electrical circuit as the boiler is strongly recommended.

Boiler water Thoroughly flush the system (without boiler con-

nected) to remove sediment. The high-efficiency heat exchanger can be damaged by build-up or corrosion due to sediment.

Do not use petroleum-based cleaning or sealing compounds in boiler system. Gaskets and seals in the system may be damaged. This can result in substantial property damage.

Leaks in boiler or piping must be repaired at once to prevent make-up water. Use this boiler ONLY in a closed-loop system. Continual fresh make-up water will reduce boiler life. Mineral buildup in heat exchangers reduces heat transfer, overheats the materi-als, and causes failure. Addition of oxygen carried in by make-up water can cause internal corrosion.

Do not add cold water to hot boiler. Thermal shock can cause heat exchanger to crack.

Freeze protection fluids NEVER use automotive or standard glycol antifreeze.

Use only freeze-protection fluids made for hydronic systems. Follow all guidelines given by the antifreeze manufacturer. Thoroughly clean and flush any re-placement boiler system that has used glycol before installing the new boiler.

Please read before proceeding

Installer Read all instructions, including this manual and all other information shipped with the boiler, before installing. Perform steps in the order given.

User This manual is for use only by a qualified heating installer/service technician. Refer to Users Information Manual for your reference.

User Have this boiler serviced/inspected by a qualified service technician, at least annually.

Failure to comply with the above could result in severe personal injury, death or substantial property damage.

Write in the CP number in the space provided on the Installation certificate on page 107 if not already shown.

When calling or writing about the boiler Please have the boiler model number from the boiler rating label and the CP number from the boiler jacket.

Consider piping and installation when determining boiler location.

Any claims for damage or shortage in shipment must be filed immediately against the transportation company by the consignee.

Commonwealth of MassachusettsWhen the boiler is installed within the Commonwealth of Mas-sachusetts, comply with the following.

This product must be installed by a licensed plumber or gas fitter.

If antifreeze is used, a reduced pressure back-flow preventer device shall be used.

If sidewall vent or vent/air is installed, see instructions on page 34.

Hazard definitionsThe following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk levels or to important information concerning the life of the product.

Indicates presence of hazards that will cause severe personal injury, death or substantial property dam-age.

Indicates presence of hazards that can cause severe personal injury, death or substantial property dam-age.

Indicates presence of hazards that will or can cause minor personal injury or property damage.

Indicates special instructions on installation, op-eration or maintenance that are important but not related to personal injury or property damage.

Part number 550-142-786/0712 5


Figure 1 Estimated GWC input at altitude

Altitude (feet) % Sea level input

1,000 972,000 933,000 904,000 875,000 835,500 826,000 807,000 778,000 749,000 72

10,000 69

Figure 2 Service clearances (recommended)

Prepare boiler locationInstallations must follow these codes: Local, state, provincial, national codes, laws, regulations and ordinances. NationalFuelGasCode,ANSIZ223.1-latestedition. StandardforControlsandSafetyDevicesforAutomaticallyFiredBoil-

ers, ANSI/ASME CSD-1, when required. NationalElectricalCode. ForCanadaonly:B149.1orB149.2InstallationCodeandCSAC22.1

Canadian Electrical Code Part 1 and any local codes.

The GWC boiler gas manifold and controls met safe lighting and other performance criteria when boiler underwent tests specified in ANSI Z21.13 latest edition.

For the Commonwealth of Massachusetts, read and follow the special instructions located on page 34 of this manual.

Install the boiler so control system components are protected from dripping or spraying water or rain during operation. Allowing these components to become wet could cause a boiler failure, resulting in severe personal injury, death or substantial property damage.

High altitude installationsGWC boiler controls automatically reduce input with increasing altitude. See Figure 1 for estimated input at altitude as a percentage of sea level input. Multiply the boiler sea level input by this percentage to obtain the estimated high altitude input. Note that the length of the venting system will also have a minor impact on input.

No modifications to the boiler should be necessary for installations up to 5,500 feet above sea level. For higher elevations, the air pressure switch must be changed to a special high altitude switch. Refer to the high altitude kit instructions, page 10. Note that the gas valve outlet pressure must be checked (and adjusted if necessary) following instructions on page 61.

DO NOT sidewall vent DIRECT EXHAUST APPLICATIONS at altitudes above 5,500 feet. Sidewall venting is only allowed for DIRECT VENT applications (ducted combustion air) at altitudes above 5,500 feet.

Vent length also affects boiler input the boiler automati-cally derates to compensate for pressure loss through the vent. See the derate values given in Figure 106, page 100. For high altitude installations, multiply the % in Figure 1 times the value shown in Figure 106 to determine input vs sea level.

Service clearancesWhen possible, install GWC boilers with clearances at least as large as shown in Figure 2 for best service access.

FlooringThe GWC boiler is approved for installation on combustible flooring, but must never be installed on carpeting.

Do not install boiler on carpeting even if foundation is used. Fire can result, causing severe personal injury, death or sub-stantial property damage.

Part number 550-142-786/07126


FoundationProvide a solid brick or concrete foundation pad if any of the following is possible:

When the floor can become flooded.

When the boiler mounting area is not level.

When a high-profile condensate pump is used, provide a foundation high enough that the GWC condensate connection is at least as high as the condensate pump inlet connection.

Figure 3 Minimum foundation dimensions (inches)

Boiler model W L H *

GWC-070 GWC-105

16 30 2

GWC-140 GWC-175

16 37 2

* Increase height if needed to ensure condensate trap outlet tee is above inlet of condensate pump, when used.

Residential garage installation

PrecautionsTake the following special precautions when installing the boiler in a residential garage. If the boiler is located in a residential garage, per ANSI Z223.1, paragraph 5.1.9:

Mount the boiler a minimum of 18 inches above the floor of the garage to assure the burner and ignition devices will be no less than 18 inches above the floor.

Locate or protect the boiler so it cannot be damaged by a moving vehicle.

Minimum clearances You can install GWC boilers in spaces smaller than Fig-

ure 2, page 6 recommended service clearances, but never smaller than shown in Figure 4.

Installations with clearances less than shown in Fig-ure 2, page 6 must have air openings sized and located as shown in Figure 4.

Always provide at least screwdriver clearance to jacket front panel screws for removal of front panel for inspection and minor service.

If the boiler cannot be serviced in place, pipe the boiler with unions and isolation valves so it can be slid out of the space and serviced in an adjacent area.

The space has to be equipped with a door so boiler can be accessed, unpiped and removed.

Prepare boiler location (continued)

Figure 4 Minimum clearances when clearances are less than recom-mended service clearances of Fig-ure 2, page 6, install as shown below:

A Area adjacent to access door must be accessible and must allow for removal of the GWC boiler for service. No other appliance or air mover (exhaust fan, etc.) may be mounted in the same space.

B Access DOOR with fresh air openingsC Provide (2) Fresh air openings Each with at

least 1 sq. inch per 1,000 Btuh of boiler input

NOTICE SPECIAL REQUIREMENTS FOR AIR OPENINGS: For installations with clearances less than recommended service clearances (Figure 2, page 6), but no less than shown in Figure 4 An access door must be provided, fitted with two air openings as shown in Figure 4. Each opening must have a free area no less than 1 square inch per 1000 Btuh input of the GWC boiler in the space. DO NOT apply the air opening sizes given in Figure 42, page 36 or Fig-ure 56, page 48.

Part number 550-142-786/0712 7


Prepare the boiler (continued)

Check orifice plate replace if necessary

The correct orifice plate must be used. Failure to do so will result in severe personal injury, death or substantial property damage. The boiler is shipped with a natural gas orifice plate. It MUST BE CONVERTED to use propane.

Natural gas:For natural gas installations, inspect the silver gas/air orifice plate marking. It must be the same as the boiler size. If the orifice plate is stamped with another size, obtain the correct plate from your whole-saler. The boiler size is stamped where the X is shown in the plate stamping, Figure 6.

Propane:

For propane installations, replace the silver gas/air orifice plate with the red/white plate, per following instructions. Ensure the red/white plate boiler size is correct for the GWC boiler being installed. The boiler size is stamped where the X is shown in the plate stamping, Figure 6.

Also fill out the propane label in the conversion kit and attach to the left side of the jacket, above the gas inlet opening, as shown in Figure 5.

Orifice plate installation, when required

Access the bottom of the blower housing as shown in Figure 5.

To inspect the plate only, read the marking on the plate edge. It must read the same as the boiler size and fuel, as follows:

Boiler model Natural gas marking Propane marking

GWC-070 NG 3 SEC LP 3 SEC




To replace the plate, using a manual screwdriver or nut driver, see Figure 6:

1. Loosen screws 1 and 2 two full turns.

2. Remove screws 3 and 4.

3. Pull the gas/air orifice plate forward to remove it.

4. Slide in the new plate as shown in Figure 6. The red side of a propane plate must go next to the blower housing.

5. Replace screws 3 and 4. Tighten all four screws securely and uni-formly. DO NOT overtighten. DO NOT exceed 40 inch-pounds torque.

6. Bend down plate label tab at score mark as shown in lower right corner of Figure 6, item 10.

DO NOT use electric or pneumatic screwdrivers to re-move or tighten the gas/air boss screws. Hand-tighten only, using manual screwdriver. Should the torque exceed 40 inch-pounds, the threaded holes could strip out, causing an inadequate seal of the orifice plate. Failure to properly seal the plate to the housing could result in a gas leak, causing severe personal injury, death or substantial property damage.

Figure 5 Check for correct gas orifice plate

A Remove jacket front panel to access the bot-tom side of the blower housing.

B Complete the propane conversion label includ-ed with the conversion kit. Install label on jacket left side, as shown.

Leave the boiler on its back, on the skid as shown, until you have checked the gas/air orifice plate and replace it if necessary.

Figure 6 Follow instructions to check or replace gas orifice plate ("X" = boiler size)

14 Screws follow instructions for loosening and tightening

5 Gas/air manifold6 Front section, bottom view, component details omitted7 Side shown must point toward air inlet hose WARNING

label side for natural gas; WHITE side for propane gas

8 Propane orifice plate, RED one side and WHITE on the other (red side must face the blower housing

9 Natural gas orifice plate, SILVER10 Orifice plate after bending along score mark label is

visible when installed

Part number 550-142-786/07128



Figure 7 Install condensate trap

A In-line flue drainB Flue drain nippleC Flue drain hoseD Flue connectionE Condensate trap teeF U-clamp and nuts (not

shown)

G Condensate drain nipple

H Condensate trap hoseJ Hose clamps

Finished assembly

Install condensate trap1. Before placing the boiler in position, install the condensate trap

line, shown in Figure 7. Items shown are provided with the boiler.

Step 1 Attach the flue drain hose (C) to the in-line flue drain nipple (B).

Step 2 Slide a screw driver or pencil through the condensate drain nipple (G). Slide the end of the screwdriver or pencil into the open end of the flue drain hose (C). Feed the in-line flue drain (A) assembly into the flue con-nection (D), guiding the flue drain hose through the con-densate drain nipple (G) with the screwdriver or pencil.

Step 3 Press the in-line flue drain (A) into the flue connection (D) and through the seal ring until it reaches the stop. Then tighten the flue connection hose clamp to secure. The flue drain hose (C) should now extend down past the end of the condensate drain nipple (G).

Step 4 Slide the U-clamp (F) over the condensate trap tee (E) and into the two holes in the rail. Attach the two nuts pro-vided to the U-clamp and tighten to secure the condensate trap tee to the rail.

Step 5 Slide the ends of the condensate trap hose (H) onto the condensate drain nipple (G) and the condensate trap tee (E). Secure the condensate trap hose at each end with the hose clamps (J).

Check the height of the condensate trap tee outlet. Before rotating the boiler into position, measure the distance from the condensate tee outlet to the bottom of the boiler mounting rails. When the boiler is place in position, the condensate tee outlet must be higher than the condensate pump inlet connection (when a con-densate pump is used). Increase the foundation height if necessary.

Part number 550-142-786/0712 9


Figure 8 Air pressure switch mounting

1 Interior panel top2 Jacket left side panel3 Air pressure switch 4 WHITE hose5 RED hose6 Mounting screws

Figure 9 Follow instructions to perform the steps shown below

Prepare the boiler (continued)Install high altitude air pressure switch when required (only above 5,500 feet)1. For installations at altitude more than 5,500 feet above sea level:

a. A special high altitude air pressure switch is required. b. The gas valve outlet pressure setting must be checked, and

adjusted if necessary, per the instructions on page 61.

Failure to check gas valve outlet pressure and adjust, if necessary, could result in severe personal injury, death or substantial property damage. Carefully follow the guidelines given in this manual.

2. Obtain the GWC high altitude kit from your local Williamson-Thermoflo distributor. The high altitude kit contains the high altitude air pressure switch.

3. See Figure 8 (switch shown with wires removed).a. Remove the two (RED) control wires from the air pressure

switch spade terminals.b. Remove the factory-installed air pressure switch (loosen top

screw and remove bottom screw holding switch to jacket in-terior panel).

c. Install the high altitude air pressure switch in the same loca-tion.

d. Carefully replace the hoses on the new switch, with the red hose on the hose barb closest to the electrical spade connectors, as shown in Figure 8. The white hose goes on the other hose barb.

e. Replace the two (RED) control wires on the new pressure switch spade terminals.

Rotate the boiler into position

Boiler is shipped on back side. It must be taken off skid and rotated into correct position.

After installing condensate line, inspecting (replacing if necessary) the gas/air orifice and installing the high altitude kit (if required), move the boiler near its position.

Figure 9 shows the boiler with the front and top panels replaced. These panels may be left off if desired until the installation has been completed.

Boiler is heavy and contains some sheet metal parts which may have sharp edges. Wear gloves when handling and take proper precautions when moving. Failure to do so will result in severe personal injury, death or substantial property damage.

Refer to Figure 9 for placement sequence as follows:

1 Wear heavy gloves carefully rotate the boiler over onto its base rail legs.

2 Clip the shipping strap securing the skid to the boiler block as-sembly. Remove the skid and strap.

3 Attach the jacket rear panel as shown using (4) #10 x screws provided in the accessory bag.

Part number 550-142-786/071210


Figure 10 Piping connections for hydrostatic testPerform hydrostatic pressure testPressure test boiler before attaching water or gas piping (except as noted below) or electrical supply. Remove jacket top panel before proceeding.

Use two wrenches when tightening water piping at boiler, using one of the wrenches to prevent the boiler interior piping from turning. Failure to support the boiler piping connections to prevent them from turning could cause damage to boiler components.

Prepare boiler for test see Figure 10Step 1 Connect a hose from water supply to fill and drain boiler

for hydrostatic test. Hose is not included with boiler.

Step 2 Connect hose to boiler drain valve. Make sure hose can also be used to drain boiler after test.

Step 3 Remove 1" nipple, 1" tee, bushing and pressure/tempera-ture gauge from accessory bag. Pipe to boiler supply con-nection as shown. Use pipe dope sparingly.

Step 4 Connect a nipple and shutoff valve to system supply connection on the 1" tee. This valve will be used to bleed air during the fill. Valve and nipple are not included with boiler.

Step 5 Connect a nipple and shutoff valve to system return connection at circulator flange. This valve will be used to bleed air during the fill. Valve and nipple are not included with boiler.

Step 6 Install a " pipe plug in the relief valve opening, top of the rear boiler section, as shown. Plug is not included with boiler.

Fill and pressure test1. Connect fill water supply through drain valve, item 2.

2. Fill boiler with water (be sure bleed valves at 4 and 5 are open).

3. When water flows from bleed valves, shut off water at drain valve.

4. Close bleed valves.

5. Slowly reopen drain valve (item 2) until test pressure of 45 PSIG (or 1.5 times boiler relief valve setting NEVER MORE than 75 PSIG) is reached on the pressure gauge.

6. Test at this pressure for no more than 10 minutes.

Do not leave boiler unattended. If the boiler is filled with cold water, the water can absorb heat from the room and expand, causing excessive pressure, resulting in severe personal injury, death or substantial property damage.

7. Make sure constant gauge pressure has been maintained through-out test. Check for leaks. Repair if found.

Leaks must be repaired at once. Failure to do so can damage boiler, resulting in substantial property damage.

Do not use petroleum-based cleaning or sealing com-pounds in boiler system. Severe damage to boiler will occur, resulting in substantial property damage.

Drain and remove fittings

1. Disconnect fill water hose from water source.

2. Drain boiler at drain valve or out hose, whichever pro-vides best access to drain. Close drain valve and remove hose after draining.

3. Remove plug (item 6) from relief valve tapping.

4. Isolation valves are required to enable servicing of the boilers temperature sensor.


Part number 550-142-786/0712 11


Install water pipingAir separatorInstall an air separator in the piping as shown in this manual. For single-zone systems, install the air separator in the return piping as shown in Figure 14, page 14. This allows mounting the automatic air vent and expansion tank off of the separator.

Install relief valve1. Install relief valve ONLY as shown in Figure 12.

2. Connect discharge piping to safe disposal location, fol-lowing guidelines in Figure 13, page 13.

Figure 12 Install and pipe relief valve

Legend

1 Jacket plug for unused relief valve jacket open-ing.

2 Jackets are provided with two relief valve open-ings because each jacket size is used for two boiler sizes. Cover the unused opening with the plug provided.

3 Boiler relief valve (from accessory bag)4 x 3 nipple, provided in accessory bag5 relief valve tapping in back section6 Connect minimum discharge piping to relief

valve. See Figure 13, page 13.

Use two wrenches when tightening water piping at boiler, using one of the wrenches to prevent the boiler interior piping from turning. Failure to support the boiler piping connections to prevent them from turning could cause damage to boiler components.

The cast iron heat exchanger return temperature must be kept at or above 140F during all times of operation to prevent possibility of corrosion due to condensation. This is done automatically, using the boiler's internal circulators. DO NOT remove or tamper with these cir-culators. Failure to comply could result in severe personal injury, death or substantial property damage.

General piping information

Minimum pipe size for boiler loop piping

Figure 11 Provide boiler loop piping no smaller than listed below (based on 20F temperature rise)

Boiler loop pipe size, Minimum

GWC-070 or 105 1

GWC-140 or 175 1

Additional limit controlsFollowing standard industry practices, if installation is to comply with ASME or Canadian requirements, an additional high temperature limit may be needed. Consult local requirements for other codes/standards to determine if needed. Wire as shown in Figure 63, page 54.

Install a manual reset high temperature limit between the boiler and the isolation valve.

Wire the manual reset limit in series with the boiler limit con-trol.

Set the manual reset limit control at least 20F above the boiler limit control setting (maximum setting 220F).

Low water cut-off, when requiredA low water cutoff device is required when boiler is installed above radiation level or by certain state or local codes or insurance companies. Use low water cutoff designed for water installations. Electrode probe-type is recommended. Purchase and install in tee in supply piping above boiler. Wire contact as shown in Figure 63, page 54.

If boiler is connected to heating coils located in air han-dling units where they can be exposed to refrigerated air, use flow control valves or other automatic means to prevent gravity circulation during cooling cycle. Circu-lation of cold water through the boiler could result in damage to the heat exchanger, causing possible severe personal injury, death or substantial property damage.

Backflow preventerWhere required by codes, install a backflow preventer in the cold water fill line, as shown in suggested piping diagrams on following pages. Install a check valve if a backflow preventer is not installed.

Part number 550-142-786/071212


Install water piping (continued)

Figure 13 Relief valve installation guidelines

To avoid water damage or scalding due to relief valve operation, as per local or state codes:

Discharge line must be connected to relief valve outlet and run to a safe place of disposal. Terminate the discharge line in a manner that will prevent possibility of severe burns or property damage should the valve discharge.

Discharge line must be as short as possible and be the same size as the valve discharge connection through-out its entire length.

Discharge line must pitch downward from the valve and terminate at least 6 above the floor drain where any discharge will be clearly visible.

The discharge line shall terminate plain, not threaded, with a mate-rial serviceable for temperatures of 375F or greater.

Do not pipe the discharge to any place where freezing could occur.

No shutoff valve shall be installed between the relief valve and boiler, or in the discharge line. Do not plug or place any obstruction in the discharge line.

Test the operation of the valve after filling and pressurizing system by lifting the lever. Make sure the valve discharges freely. If the valve fails to operate correctly, replace it with a new relief valve.

Failure to comply with the above guidelines could result in failure of the relief valve to operate, resulting in possibility of severe personal in-jury, death or substantial property damage.

Expansion tank

Figure 14, page 14 and Figure 15, page 14 show typical installation of the expansion tank. Always locate the air separator and expansion tank as shown in the suggested piping drawings, beginning with Figure 17, page 16.

Ensure that the expansion tank size will handle boiler and system water volume and temperature. See tank manufacturers instructions and rat-ings for details. Additional tanks may be added to the system if needed to handle the expansion. These tanks may be installed by connecting to tees in the system piping.

Undersized expansion tanks cause system water to be lost from the relief valve and makeup water to be added through the fill valve. Eventual section failure can result. Always locate the cold water fill connection at the expansion tank. Never locate this elsewhere in the system.

Diaphragm- or bladder-type tank:

Refer to Figure 14, page 14 for suggested piping when using a diaphragm- or bladder-type expansion tank.

Diaphragm- or bladder-type expansion tank Control fill pressure with the tank air charge pressure. Always check pressure and charge tank with tank removed from system to be sure reading is accurate. Boiler relief valve is set for 30 PSIG. Operating pressure of system, after temperature expan-sion above cold fill pressure, should not exceed 24 PSIG to avoid weeping of relief valve.

Install an automatic air vent on top of the air separator, per separator manufacturers instructions.

Closed-type expansion tank:

Figure 15, page 14 shows suggested piping when using a closed-type expan-sion tank, in which the air is directly in contact with tank water.

Connect piping ( or ) from the air separator top outlet to the tank fitting. Slope any horizontal piping a minimum of 1 inch per 5 feet of horizontal pipe.

Always use a tank fitting, such as the B&G Tanktrol or Taco Taco-Trol (shown). The fitting reduces gravity flow of water in the piping to the tank, avoids air bubbling through the tank water, and provides the proper fill height in the tank.

Correct all leaks in the system or tank piping. Leaks allow air to escape from the system and will cause water-logging of the tank. This will result in water loss through the boiler relief valve due to over-pressurization.

NEVER use an automatic air vent in a system equipped with a closed-type expansion tank. The air removed from the system will cause water-logging of the expansion tank.

Closed-type expansion tank Follow tank manufacturers instructions for filling the tank. Typical tank sizing provides for approximately 12 PSIG when the tank is filled to the normal level and system water is cold. Note that boiler relief valve is set for 30 PSIG. Operating pressure of system, after temperature expansion above cold fill pressure, should not exceed 24 PSIG to avoid weeping of relief valve.

Part number 550-142-786/0712 13


Figure 14 Piping to single-zone system using diaphragm- or bladder-type expansion tank. Boiler connections are 1 NPT (supply from 1 tee, return to 1 recuperator flange).

Figure 15 Piping closed-type expansion tank

Pipe diaphragm- or bladder-type expansion tanks to the bot-tom of the separator.

Pipe closed-type (air in contact with water) tanks to the top of the air separator. Always connect the fill line to the expansion tank location, as shown above and in the suggested piping.


Legend

1 Relief valve discharge piping see page 122 Isolation valves3 Fill valve4 Diaphragm-type expansion tank always locate as

shown in the suggested piping drawings in this manual

5 Air separator provide with automatic air vent ONLY when used

with diaphragm-type expansion tanks

pipe air outlet to expansion tank when used with close-type tanks

6 Cold fill line, with backflow preventer or check valve when required by codes (see Figure 15 for typical com-ponents)

7 System supply piping8 System return piping10 Pressure reducing valve, when used11 Quick-fill bypass valve, when used12 Closed-type expansion tank always locate as shown

in the suggested piping drawings in this manual

13 Tank fitting

Part number 550-142-786/071214


Install water piping (continued)System water piping methods

Most piping methods shown in this manual use primary/secondary connection to the boiler loop. These designs ensure proper flow through the GWC boiler, for the most efficient and reliable operation of the boiler and the heating system. For other piping methods, consult your local Williamson-Thermoflo representative.

Circulators

Do not remove either of the GWC internal pumps for use elsewhere in the system. Both pumps are required for proper operation. Removing a pump will cause the boiler to malfunction. Substantial property damage could result.

Never install another pump in series with the GWC boiler. Forced flow can cause improper op-eration of the boiler controls. Substantial property damage could result.

Failure to comply could result in unreliable perfor-mance and nuisance shutdowns from insufficient flow.

Circulator flow rateSize system circulators based on the flow rate required to achieve the temperature change needed. You can closely estimate tem-perature rise (or drop) through a circuit by using the following formula, where TD is temperature rise (or drop), FLOW is flow rate (in gpm), and BTUH is the heat load for the circuit:

FLOW =BTUH

TD x 500

Examples:

Consider a system loop for a system with total heating load equal to 210,000 Btuh. The desired temperature drop through the system piping is 20F. Then the required flow rate is:

FLOW =210,000

20 x 500

= 21 gpm

SIMPLIFIED: For 20 temperature drop, FLOW = MBH / 10.

Circulator head requirementThe circulator must be capable of delivering the required flow against the head loss that will occur in the piping. Determine the pipe size needed and the resultant head loss using accepted engineering methods. The simplified pipe sizing here is limited to residential systems, and does not include systems with fan coil units or radiant tubing.

The following simplified method for pipe and cir-culator sizing must be limited to residential applica-tions using baseboard (finned or cast iron), cast iron radiators or convectors. DO NOT apply for radiant heating, fan coil units or commercial installations.

Simplified pipe/circulator selection1. Install the boiler and piping using the recommended piping

layouts in this manual.

2. Size the piping and components for each circuit in the space heating system using Figure 16. At the flow rates listed, the head loss in all piping will be 0.04 feet per foot of pipe.a. Determine the heating load (Btuh) for each circuit.b. Calculate the flow rate for each circuit using its load. To use a 20F temperature drop, just divide the

MBH (1,000s of Btuh) by 10. Example Flow for 20F temp drop with 35,000 Btuh: FLOW = 35 MBH / 10 = 3.5 gpm

c. Find the pipe size in Figure 16 that has a max flow rate just larger than that required for the circuit.

d. Find the total equivalent length (TEL) of the circuit. TEL accounts for losses through fittings and valves by

using the equivalent length of pipe that would cause the same head loss. Add these numbers to the measured length of the circuit to find TEL in feet.

TEL is usually close to 1.5 times the length of the circuit for residential baseboard, radiator or convec-tor applications.

e. Measure the length of each circuit from the circulator outlet back to its inlet. Then multiply this length times 1.5 to get the approximate TEL of the circuit.

f. Find the head loss for each circuit:

TEL = 1.5 X Circuit Length (feet)HEAD = TEL X 0.04 (feet water column)

g. NOTE: Size system header piping for the total flow of all connected zones.

3. Example: a. For a circuit with heating load = 45,000 Btuh (= 45

MBH). Measured length of circuit is 88 feet.b. Flow = 45 MBH / 10 = 4.5 gpm.c. TEL = 1.5 x 88 feet = 132 feet.d. From Figure 16, select 1" pipe (max flow = 8 gpm).e. Head loss = TEL x 0.04 = 132 x 0.04 = 5.28 feet.f. Select a circulator that can deliver at least 4.5 gpm at a

head of 5.28 feet. (Read the NOTICE below.)

To use this method, limit the flow through " finned-tube baseboard to 3.9 gpm, or use 1" base-board and limit flow to 7.1 gpm. If the total load of the circuit requires more flow, split the circuit into two or more.

Figure 16 Flow rates for 0.04 feet head loss per foot of copper pipe (based on water at140F)

Pipe size (inches)

MAX Flow rate (GPM) @ 0.04 feet per foot

Pipe size (inches)

MAX Flow rate (GPM) @ 0.04 feet per foot

4 2 45

1 8 2 75

1 14 3 140

1 22 4 290

Part number 550-142-786/0712 15


Figure 17 Baseboard system circulator zoningBaseboard system piping CIRCULATOR zoning (primary/secondary)Apply Figure 17 for circulator zoning on systems using baseboard heaters. The heaters can be any baseboard style, including finned tube or cast iron.

Zoning with circulators The GWC internal system circulator cannot be removed from the boiler for use as one of the zone circulators. It must remain as shipped from the factory to allow proper flow control inside the boiler. You will need a circulator for each zone. Provide circulator relays or circulator zone controller.

Baseboard system piping ZONE VALVE zoning (direct connection)The boiler internal circulator can be used to circulate many zone-valve zoned systems as shown in Figure 18, page 17 for application on systems using baseboard (finned tube or cast iron).

DO NOT apply this piping when using a GWC-175 the internal circulator cannot supply enough flow to the system.

When applying Figure 18, page 17, DO NOT exceed the limits shown in Figure 19, page 17.

For systems requiring higher flow or head loss, apply the suggested piping of Figure 20, page 18, NOT that of Fig-ure 18, page 17.

Balancing, when required Substitute a memory-stop valve for one of the isolation valves in each zone to use the memory-stop valve for balancing flow as well as isolation.

Zoning with zone valves Provide a separate 24-volt transformer to power the zone valves. Size the trans-former to handle the total rated load of all connected zone valves. Alternatively, use a zone valve zone controller.

Do not use R & C connections for zone valve.

DO NOT connect directly from 3-wire zone valves to the T-T terminals on the boiler. When using 3-wire zone valves, install an isolation relay. Connect the zone valve end switch wires to the isolation relay coil. Connect the isolation relay contact across the boiler T-T termi-nals. Failure to comply can result in damage to boiler components or cause unreliable operation, resulting in severe property damage.

Applying Figure 18, page 171. Figure 18, page 17 and Figure 19, page 17 provide guidelines for

checking whether the GWC internal circulator can provide suffi-cient flow when directly connected to a two-pipe baseboard system.

The outputs of GWC boilers are all too high for con-nection to a single-loop series-loop system. To apply to an existing series loop system, the system must be fitted with trunk lines to convert to a split-loop system. Pro-vide either one or two trunk lines to meet the minimum number of circuits and maximum loading per circuit given in Figure 19, page 17.

2. The system pipe sizing must be no smaller than shown in the Legend for Figure 18, page 17.

3. Values shown for maximum circuit lengths, maximum load per circuit and the maximum feet baseboard per circuit are limits that ensure the internal circulator will have sufficient head to provide the flow needed for each circuit.

MINIMUM Boiler loop pipe size

GWC-070/105 GWC-140/175

11

Legend

1 Isolation valves

2 Automatic air vent (with diaphragm-type expan-sion tank), or connect to tank fitting (closed-type expansion tank).

3 Diaphragm- or bladder-type expansion tank, if used. (For closed-type expansion tank, pipe from top of air separa-

tor to tank fitting as in Figure 15, page 14.)

5 Zone circulator

6 Flow/check valve

7 Hose bibb purge valve

8 Boiler pressure/tempera-ture gauge

16 Cold water fill line see Figure 15, page 14 for typical components


Part number 550-142-786/071216


Legend

1 Isolation valves

2 Automatic air vent (with diaphragm-type expan-sion tank), or connect to tank fitting (closed-type expansion tank).

3 Diaphragm- or bladder-type expansion tank, if used. (For closed-type expansion tank, pipe from top of air separator to tank fitting as in Fig-ure 15, page 14.)

4 Zone valve


8 Boiler pressure/tempera-ture gauge

10 Differential pressure by-pass valve


Pipe sizes (NPT), minimum

Boiler modelMains Circuits

GWC-070 GWC-105

1" "

GWC-140 1" "

Circuit requirements

See Figure 19


Figure 18 Zone valve zoning GWC-070, GWC-105 or GWC-140 (DO NOT apply to GWC-175)

Figure 19 The system must meet the following requirements when applying Figure 18

Boiler model

Circulator HEAD available to the

system

Maximum circuit length

L

Minimum number

of circuits

Max load of any circuit

Max feet baseboard of any circuit

(@ 600 Btuh/foot)

Summary

GWC-0706.4 feet w.c. @ 6.5 GPM

103 feet 2 40 MBH 67 feet6.5 GPM total

(max 4GPM any cricuit) 20F temperature drop

GWC-1054.1 feet w.c. @ 9.7 GPM

92 feet 3 33 MBH 55 feet9.7 GPM total

(max 3.3 GPM any circuit) 20F temperature drop

GWC-140 *5.5 feet w.c. @8.7 GPM

112 feet 3 53 MBH 88 feet8.7 GPM

(max 3.5 GPM any circuit) 30F temperature drop

GWC-175 DO NOT apply to GWC-175 Use primary/secondary piping ONLY, as in Figure 20, page 18.

* This application may be marginal. It could cause temperature distribution problems, because the temperature drop is 30F, NOT 20F. The best method is to use primary/secondary piping for the GWC-140 as in Figure 20, page 18.

One-pipe diverter tees systems The ap-plication information on this page is based on two-pipe baseboard systems. To check whether the internal circulator can provide sufficient flow to a one-pipe diverter tee system, use the available head value given in Figure 19, page 17.

Part number 550-142-786/0712 17


Figure 20 Radiator system zone-valve zoning

Figure 21 Radiator system circulator zoning

Radiator system pipingApply Figure 20 (zone-valve zoning) or Figure 21 (circulator zoning) to systems using standing cast iron radiators. This applies to gravity water systems and converted steam systems using columnar, tubular or recessed cast iron radiators.

The suggested piping for zone-valve zoning radiator systems differs from baseboard systems because of the high water content of cast iron radiators. The GWC internal circulators automatically regulate supply and internal bypass flow based on the temperature of the water return-ing to the boiler. At the start of many heating cycles in a radiator system, the water in the radiators is cool. So the boiler would slow down system flow rate while sending out relatively hot water. This could cause heat distribution problems. Install a separate system circulator as shown in Figure 20 when zoning with zone valves. The separate circulator assures a relatively constant temperature drop through the system.

The boiler internal circulators must be left in the boiler. They cannot be removed for use a zoning circulator. Provide a circulator for each zone when circulator zoning, and pipe the system as in Figure 21.





The system circulator must be supplied by the in-staller.


GWC-070/105 GWC-140/175

11


GWC-070/105 GWC-140/175

11

Legend

1 Isolation valves

2 Automatic air vent (with diaphragm-type expansion tank), or connect to tank fitting (closed-type expansion tank).

3 Diaphragm- or bladder-type expansion tank, if used. (For closed-type expansion tank, pipe from top of air separator to tank fitting as in Figure 15, page 14.)

4 Zone valve

5 System or zone circulator

6 Flow/check valve


8 Boiler pressure/temperature gauge

9 System supply temperature gauge




(Optional)

Part number 550-142-786/071218


Figure 22 Single-zone radiant heating or heat pump system

Single-zone radiant heating or heat pump

Radiant heating systems and heat pump systems usually require system supply water temperatures below 140F. But the boiler outlet water temperature will be at least 150F to 160F during most operat-ing conditions. So the piping must include a method of reducing the supply water temperature to the system.

Figure 22 uses two balancing valves to manually adjust the supply water temperature. Follow the instructions below to adjust these valves. Install the supply temperature limit control (item 14) as shown to protect the system from over-temperature conditions. Note also that this piping requires a separate system circulator, as shown, because of the higher flow rates of radiant and heat pump systems.

Manual adjustment of the supply temperature is limited to single-zone systems because multi-zone systems will cause varying loads, making it unlikely an acceptable valve setting could be found. See Figure 23, page 20 or Figure 24, page 20 for multi-zone systems.

You may also apply the suggested piping of either Figure 23, page 20 or Figure 24, page 20 if you want automatic supply temperature regulation or outdoor reset temperature control.

For additional information and alternatives in piping for radiant heat-ing systems, contact Williamson-Thermoflo.

The system circulator must be supplied by the in-staller.

Adjust balancing valves

Use valves 17 and 18 to mix boiler supply water with system return water, reducing supply water temperature to the system.

1. Subtract the design system supply temperature from 150F. Call this number the temperature difference.

2. Open valve 17 and close valve 18.

3. Start the boiler and system.

4. Let the system warm up for about 15 minutes.

5. Note the temperature at gauge 9 (system supply) and gauge 8 (boiler supply).

6. Slowly close valve 17 while opening valve 18 until gauge 9 reads lower than gauge 8 by at least the temperature difference found in step 1.

7. Example: For a design supply temperature of 100F, the tempera-ture difference would be 150F minus 100F, or 50F. Set the valves until gauge 9 reads at least 50F lower than gauge 8.


GWC-070/105 GWC-140/175

11

Legend

1 Isolation valves

2 Automatic air vent (with diaphragm-type expansion tank), or connect to tank fitting (closed-type expan-sion tank).

3 Diaphragm- or bladder-type expansion tank, if used (For closed-type expansion tank, pipe from top of air separator to tank fitting as in Figure 15, page 14.)

5 System circulator




10 Return temperature gauge

14 Supply temperature limit control Set at a tempera-ture below the maximum allowed for the system or as directed by the system designer.


17 Balancing valve

18 Balancing valve


Part number 550-142-786/0712 19


Figure 23 Auto system supply temp regulation zone valve zoning

Figure 24 Auto system supply temp regulation circulator zoning

Multi-zone radiant heating systemMulti-zone systems require automatic regulation of the system sup-ply temperature because of widely varying load conditions. Figure 23 (zone-valve zoning) and Figure 24 (circulator zoning) show suggested piping for these systems.

Provide an automatic temperature control valve or motor-operated valve which can be adjusted for the desired supply water temperature. This is required to protect the radiant system from excessive temperature.

Zone-valve zoning The suggested piping uses a separate circulator for system circulation to provide the higher flow typical of radiant heating systems and to assure good temperature distribution in the system when the return water temperature is low.

Circulator zoning The GWC internal circulators must not be re-moved. Provide a separate circulator for each zone.


Zoning with zone valves Provide a separate 24-volt transformer to power the zone valves. Size the transformer to handle the total rated load of all connected zone valves. Alternatively, use a zone valve zone controller.


Zoning with circulators The GWC internal system circulator cannot be removed from the boiler for use as one of the zone circulators. It must remain as shipped from the factory to allow proper flow control inside the boiler. You will need a circulator for each zone. Provide circulator relays or circulator zone controller. The sys-tem circulator must be supplied by the installer.

Outdoor resetApply Figure 23 or Figure 24 for any system intended for outdoor reset of the supply water temperature. Use a motor-operated three-way valve and an outdoor reset temperature control system.


GWC-070/105 GWC-140/175

11


GWC-070/105 GWC-140/175

11

Legend 1 Isolation valves 2 Automatic air vent (with diaphragm-type expansion tank), or

connect to tank fitting (closed-type expansion tank). 3 Diaphragm- or bladder-type expansion tank, if used (For closed-

type expansion tank, pipe from top of air separator to tank fitting as in Figure 15, page 14.)

4 Zone valve 5 System or zone circulator 6 Flow/check valve 7 Hose bibb purge valve 8 Boiler pressure/temperature gauge 9 System supply temperature gauge10 Supply temperature automatic mixing valve11 Differential pressure by-pass valve16 Cold water fill line see Figure 15, page 14 for typical components


Part number 550-142-786/071220


Figure 25 Auto return temp regulation circulator zoning

Piping snow melt systems or combination snow melt/space heating systemsCombination snow melt/space heating systems can have return water temperature below 60F, and the return temperature will fluctuate. So these systems require automatic return water temperature as shown in Figure 25 (zone-valve zoning) or Figure 26 (circulator zoning).

Select an automatic temperature control valve or motor-operated valve which can be adjusted to provide a return water temperature of at least 60F. Any setting higher than 60F will also be acceptable.

Zone-valve zoning The suggested piping uses a separate circulator for system circulation to assure good temperature distribution in the system when the return water temperature is low.

Circulator zoning The GWC internal circulators must not be re-moved. Provide a separate circulator for each zone.

The return water temperature to the boiler must be at least 60F. Provide and apply means to regulate the return temperature. Failure to do so can result in boiler control operation problems, causing possible significant property damage.

Zoning with zone valves Each zone in the piping diagrams in this section is shown with an isolation valve on each side. Substitute a memory-stop valve for one of these in each zone in order to use the memory-stop valve for balancing flow as well as isolation.

Provide a separate 24-volt transformer to power the zone valves. Size the transformer to handle the total rated load of all connected zone valves.


Zoning with circulators The GWC internal system circulator cannot be removed from the boiler for use as one of the zone circulators. It must remain as shipped from the factory to allow proper flow control inside the boiler. You will need a circulator for each zone. Provide circulator relays or circulator zone controller. The sys-tem circulator must be supplied by the installer.


GWC-070/105 GWC-140/175

11


GWC-070/105 GWC-140/175

11

Legend 1 Isolation valves

2 Automatic air vent (with diaphragm-type expansion tank), or connect to tank fitting (closed-type expansion tank).

3 Diaphragm- or bladder-type expansion tank, if used (For closed-type expansion tank, pipe from top of air separator to tank fitting as in Figure 15, page 14.)

4 Zone valve

5 System or zone circulator

6 Flow/check valve




10 Return temperature automatic mixing valve



Figure 26 Auto return temp regulation zone valve zoning


Part number 550-142-786/0712 21


Figure 27 Installing GWC boiler in system with water chiller

Water chiller systemsPipe the boiler and water chiller as shown in Figure 27.

Install boiler, as shown, so chilled medium is piped in parallel with heating boiler.

Use appropriate valves to prevent chilled medium from entering boiler. See Figure 27 for typical installation of balancing valve and check valve.

Install the flow/check valve in the boiler supply piping, as shown in Figure 27, to prevent gravity circulation during the cooling cycle.

If boiler is connected to heating coils located in air handling units where they can be exposed to refrigerated air, use flow control valves or other automatic means to prevent gravity circulation during cooling cycle.





Chilled water systems often use closed-type expansion tanks, as shown in Figure 27. DO NOT install automatic air vents on these systems.


GWC-070/105 GWC-140/175

11


Legend

1 Isolation valves

2 Air separator

3 Expansion tank with tank fitting (piping shown for application of a closed-type expansion tank)

5 System circulator

6 Flow/check valve



17 Balancing valve

19 Chiller

20 Strainer

21 Check valve

22 System supply

23 System return

Part number 550-142-786/071222


Multiple boiler installationsPlacing multiple boilers1. Locate multiple boilers in boiler room according

to:a. Figure 28 (side-to-side), orb. Figure 29 (back-to-back).

2. Provide the clearances indicated in the illustrations listed above to provide for access and servicing. If these recommended dimensions are not possible, provide at least the recommended service clearances given on page 6. Also follow local codes.

3. Construct boiler foundation if boiler room floor is uneven or if there is a danger of flooding. Size foundation to allow for clearance and spacing di-mensions shown in the illustrations at right.

4. Chalkline boiler locations on foundation or boiler room floor.

5. Uncrate, assemble and mount boilers according to instructions in this manual.

6. Provide clearance for installation of venting, air piping, gas piping, expansion tank, primary circula-tor and other accessories.

Controlling multiple GWC boilers1. Multiple GWC boilers can be controlled using any

boiler control/sequencing system that provides an isolated contact for call for heat (connected to the boiler's T-T terminals).

Piping multiple GWC boilers1. See suggested piping diagrams in this manual.

Contact Williamson-Thermoflo for assistance for systems not covered.

2. Always pipe the boilers on a secondary loop in a primary/secondary circuit as shown in the examples in this manual.

Figure 28 Side-to-side mounting of multiple GWC boilers, showing RECOMMENDED clearances

Figure 29 Back-to-back installation of multiple GWC boilers, showing RECOMMENDED clearances

Part number 550-142-786/0712 23


Multiple boiler water pipingSecondary header piping installation

1. Main header and secondary header pipe sizing.

a. New system See page 15.

b. Replacing boilers in an existing system Without reducing size, connect system supply and return lines. Install tees or crosses for secondary headers as shown in Figure 30 or Fig-ure 31. Size headers to handle total connected boiler output as shown.

2. Provide connections in main header for secondary headers as close as possible to the midpoint of multiple boilers.

a. Use tees for four or less boilers, as in Figure 30.

b. Use either tees (Figure 30) or crosses (Figure 31) for five or more boilers.

3. Secondary header placement:

a. To alternate spacing for supply and return lines to boilers, reverse the short-end and long-end of the headers as shown in Figure 30 and Figure 31.

b. Return header must be on the return side of the main and sup-ply header must be on the supply side of the main. Drawings in this manual show flow in system main from right to left. For system flowing left to right, reverse the locations of the manifolds accordingly.

4. Connect from secondary header branches to boiler supply and return connections using copper or steel pipe, sized for the re-quired flow rate.

5. Provide a flow/check valve in the supply piping of each boiler as shown in piping diagrams in this manual. Install an isolation valve on the supply and return of each boiler as shown. Some local codes may require the use of individual water level controls and limits on each boiler when isolation valves are installed.

6. Install main system air eliminator and primary circulator in sup-ply piping as shown in piping diagrams. Place expansion tank on suction side of system circulator as shown.

7. Install system accessories as shown in drawings.

8. Piping recommendation drawings:

a. Figure 30 and Figure 31 show details of secondary headers.

b. Figure 32, page 25 is a schematic piping drawing showing the locations of typical boiler piping and system piping, including limits and other devices often required by local codes.

c. Figure 33, page 26 and Figure 34, page 27 are three-dimensional piping drawings of typical multiple boiler installation.

d. Figure 35, page 28 shows recommended piping when an isolat-ing heat exchanger is needed.

9. If desired, other primary/secondary piping arrangements can be used.

When using isolation valves on each boiler, some codes may require providing a low water control and additional limit for each boiler. Consult local codes to determine if omission of the individual boiler isolation valves may allow the use of a single water level control and additional limit for the entire multiple boiler system.

Maximum connected load per header:2-inch header 450 MBH3-inch header 1400 MBH4-inch header 2900 MBH

Figure 30 Single-sided secondary header, typical

Figure 31 Double-sided secondary header, typical

Part number 550-142-786/071224


Multiple boiler water piping (continued)

Legend Figure 32

1 Flow/check valve (each boiler)

2 Isolation valves (when used)

3 Cap

4 Secondary header (supply) layout and size per page 24

5 Secondary header (return) layout and size per page 24

6 Primary circulator

7 Expansion tank (diaphragm type)

8 System air eliminator

9 System automatic air vent

10 Pressure reducing valve

11 Check valve or backflow preventer, as required by applicable codes

12 Isolation valve

13 Water flow switch (when used)

14 Supply water temperature control (when used)

15 Low water cutoff (when used) (place above primary header)


18 System supply

19 System return

20 (Not shown) Boiler relief valve and discharge piping, installed per GWC Boiler Manual

30 Long end of secondary header

Figure 32 Piping schematic typical for multiple GWC boilers, using secondary headers

Part number 550-142-786/0712 25



Legend Figure 33 1 Flow/check valve (each boiler) 2 Isolation valves (when used) 3 Caps 4 Secondary header (supply) layout and size per page 24 5 Secondary header (return) layout and size per page 24 6 Primary circulator 7 Expansion tank (diaphragm type) 8 System air eliminator 9 System automatic air vent16 Cold water fill line see Figure 32, page 25 for typical com-

ponents

17 3-way diverting valve (operated by DHW aquastat valve end switch connects across boiler thermostat terminals)

18 System supply

19 System return

20 Boiler relief valve and discharge piping, installed per GWC Boiler Manual

21 Indirect-fired storage water heaters Example is shown connect-ed to one boiler of the system. The indirect water heater could also be connected with a secondary connection off the main header, as in Figure 34, page 27.

Figure 33 Piping layout typical for multiple GWC boilers, using secondary headers (2-boiler system)

Part number 550-142-786/071226


Figure 34 Piping layout typical for multiple GWC boilers, with DHW storage heaters (4-boiler system)

Suggested DHW boiler-side pipe sizing (for max 0.04 feet head loss per foot of total equivalent length, TEL)

Flow rate Size Flow rate Size

1 4 gpm 22 45 gpm 2

4 8 gpm 1 45 75 gpm 2

8 14 gpm 1 75 - 140 gpm 3

14 22 gpm 1 140 290 gpm 4

Legend Figure 34 1 Flow/check valve (each boiler)


3 Caps

4 Secondary header (supply) layout and size

per page 24

5 Secondary header (return) layout and size

per page 24

6 Primary circulator

7 Expansion tank (diaphragm type)



16 Cold water fill line see Figure 32, page 25

for typical components

18 System supply

19 System return

20 Boiler relief valve and discharge piping,

installed per GWC Boiler Manual

21 Indirect-fired storage water heaters Example is shown with a boiler

water circulator on each water heater. Alternatively, the water heaters could

be connected with reverse return piping, using a common circulator.

22 Boiler water inlet

23 Boiler water outlet

24 DHW boiler-side circulators

25 DHW boiler-side return secondary header

26 DHW boiler-side supply secondary header

27 Flow/check valves (to prevent induced or gravity flow in heating system or

DHW piping)

28 Check valve to prevent heat migration in heating system

29 Drain valves

30 Sensor for BCP (boiler control panel), when used

Note: See water heater manual for DHW piping The DHW piping must also

be manifolded together since the boiler-side piping is manifolded. If DHW

heaters supply separate DHW circuits, provide an individual circulator for

each water heater, and control each circulator by its water heaters aquastat.

This piping is sug-gested only. The

layout above should be controlled with a boiler sequencing panel that provides DHW operation as well. Wire the heating system circulator to operate only on call for heat. Al-ternatively, use the boiler sequencing panel to provide domestic priority by disabling the heating system cir-culator any time there is a DHW call for heat. The boiler internal circula-tors operate on any call for heat, whether heating system or DHW. Offset the DHW boiler-side supply and return manifolds as shown so the total run of pipe and fittings to each of the water heaters is approxi-mately equal.


Part number 550-142-786/0712 27



Figure 35 Piping layout typical for multiple GWC boilers, using isolation exchanger

Legend Figure 35 1 Flow/check valve (each boiler)


3 Cap

4 Secondary header (supply) layout and size per page 24

5 Secondary header (return) layout and size per page 24

6a Heating system circulator (exchang-er tube-side)

6b Heat exchanger shell-side circulator

7 Expansion tanks (diaphragm type)



13 Cold water supply connections

16 Cold water fill line see Fig-ure 32, page 25 for typical compo-nents

18 Heating system supply

19 Heating system return

20 Boiler relief valve and discharge pip-ing, installed per GWC Boiler Manual

30 Sensor for BCP (boiler control panel), when used

Notes:1. Contact heat exchanger manufacturer for heat ex-

changer shell-side and tube-side piping and circulator requirements. Tube-side flow and temperatures must meet heating system requirements.

2. Contact heat exchanger manufacturer for sizing heat exchanger.

3. Heat exchanger shell-side circuit requires its own expansion tank as shown.

4. Heating system circuit requires its own expansion tank, as shown, plus its own relief valve set to protect heating system and heat exchanger piping and components.

5. When individual isolation valves are used, individual boiler and level controls may be required.

Use isolation heat exchanger for:

1. Large volume systems with high mineral content in water.

2. Systems exposed to untreated quantities of makeup water.

3. Old systems severely contami-nated with scale and rust buildup inside piping and heat distribu-tion units.

4. Process applications.5. Commercial service water ap-

plications.6. High water pressure applications,

requiring pressure relief setting in heating system more than 50 PSIG (tall buildings). See notes below.

Part number 550-142-786/071228


Venting & air general

GWC boilers must be vented and supplied with combustion and ven-tilation air using piping and methods described in this manual.

Every boiler must have its own vent. DO NOT common vent with any other appliance.

Inspect finished vent and air piping thoroughly to ensure all are airtight and comply with the instructions provided and with all requirements of applicable codes.

Failure to provide a properly-installed vent and air system will cause severe personal injury or death.

If the vent/air piping configurations covered in the GWC boiler manual cannot be applied for a particular installation, contact Williamson-Thermoflo for assistance. Other con-figurations may be available.

Where vent piping is routed through an unheated space, apply minimum 1 inch of foil-faced fiberglass insulation on the length of the vent pipe in the unheated space.

Installations must comply with local requirements and with the National Fuel Gas Code, ANSI Z223.1 for U.S. installations or CSA B149.1 or B149.2 for Canadian installations.

Use only the materials listed in this manual for vent and air pipe and fit-tings. See Figure 40, page 33.

If used, a masonry chimney can ONLY be used as a PIPE CHASE for vent and air pipes The vent and air piping must be installed as instructed in this manual and all joints must be sealed. The chimney must be used only for GWC boilers. NO OTHER appli-ance or fireplace can be connected to the chimney. The chimney must be straight, with no offsets, and the vent and air piping materials must comply with this instruction manual. The chimney must be fitted with a sealed access opening, through which the in-terior of the chimney can be inspected. The chimney (and liner, if installed) must be inspected at least once annu-ally to verify condition.

Failure to comply could result in severe personal injury, death or substantial property damage.

When removing a boiler from an existing common vent system

The GWC boiler cannot be common vented with any other ap-pliance. When an existing boiler is replaced with a GWC boiler, the GWC boiler CANNOT use the existing common vent. The GWC boiler requires its own vent and air piping, as specified in this manual. This may cause a problem for the appliances that remain on the old common vent, because the vent may be too large. The following test, required by ANSI Z21.13, is intended to check for proper operation of the appliances remaining on the old common vent system.

Vent system verification

At the time of removal of an existing boiler, the following steps shall be followed with each appliance remaining connected to the common venting system placed in operation, while the other appliances remaining connected to the common venting system are not in operation. Seal any unused open-ings in the common venting system.

Existing vent test procedure

(The following is intended to test whether the appliances remaining on an existing vent system will operate satisfactorily.)

1. Visually inspect the venting system for proper size and horizontal pitch and determine there is no blockage or restriction, leakage, corrosion or other deficiencies which could cause an unsafe condition.

2. Test vent system Insofar as is practical, close all building doors and windows and all doors between the space in which the appliances remaining connected to the common venting system are located and other spaces of the building. Turn on clothes dryers and any appliance not connected to the common venting system. Turn on any exhaust fans, such as range hoods and bathroom exhausts, so they will oper-ate at maximum speed. Do not operate a summer exhaust fan. Close fireplace dampers.

3. Place in operation the appliance being inspected. Follow the lighting in-structions. Adjust thermostat so appliance will operate continuously.

4. Test for spillage at draft hood relief opening after 5 minutes of main burner operation. Use the flame of a match or candle, or smoke from a cigarette, cigar, or pipe.

5. After it has been determined that each appliance remaining connected to the common venting system properly vents when tested as outlined herein, return doors, windows, exhaust fans, fireplace dampers, and any other gas-burning appliance to their previous conditions of use.

Any improper operation of common venting system should be corrected so the installation conforms with the National Fuel Gas Code, ANSI Z223.1 latest edition. Correct by re-sizing to approach the minimum size as determined using the appropriate tables in Part 11 of that code. Canadian installations must comply with B149.1 or B149.2 Installation Code.

Part number 550-142-786/0712 29


Venting & air general (continued)Provide combustion air:

DIRECT VENT The installation must provide com-bustion air piping. In addition, ventilation openings may be required.

DIRECT EXHAUST The installation must provide combustion air openings to the boiler space.

ALL APPLICATIONS The installation must provide combustion air openings as needed for other appli-ances in the space.

Vent and air termination options1. Vent and air piping must terminate out the sidewall or through the

roof of the building, using only one of the methods described in this manual. See Figure 39, page 32 and Figure 40, page 33 for allowable configurations and piping materials.

DIRECT VENT installations1. For direct venting, combustion air must be piped from outside to the

boiler, following the instructions in this manual, and compliant with all applicable codes.

2. Ventilation openings are required for some spaces. See Fig-ure 42, page 36.

3. If other appliances are located in the same space with the GWC boiler, provide openings shown in Figure 42, page 36.

If combustion and ventilation air openings are not provided as directed above and the room does not have adequate ventilation, the higher temperature in the space may result in reduced component life.

DIRECT EXHAUST installations1. Combustion and ventilation air must be provided in the boiler room

on direct exhaust installations. Follow all instructions in this manual (see page 47 for air opening instructions) and all applicable codes to provide required air openings.

DO NOT sidewall vent DIRECT EXHAUST APPLICATIONS at altitudes above 5,500 feet. Sidewall venting is only allowed for DIRECT VENT applications (ducted combustion air) at altitudes above 5,500 feet.

Combustion air contamination:

Ensure that the combustion air will not contain any of the contaminants in Figure 36.

DO NOT place combustion air supply openings or intake terminations near a swimming pool, for example.

Avoid areas subject to exhaust fumes from laundry facilities. These areas will always contain contaminants.

Figure 36 Corrosive contaminants and sources

Products to avoid

Spray cans containing chloro/fluorocarbons

Permanent wave solutions

Chlorinated waxes/cleaners

Chlorine-based swimming pool chemical

gwc - gas water condensing installation manual (38.64 mb)

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